<template>
    <div>
        <router-link 
            tag="div"
            to="/"
            class="header-abs"
            v-show="showAbs"
            >
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div 
            class="header-fixed" 
            v-show="!showAbs"
            :style="opacityStyle"
            >
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>

<script>
import CommonGallary from 'common/gallary/Gallary'
export default {
  name: 'DetailHeader',
  data() {
      return {
          showAbs: true,
          opacityStyle:{
              opacity:0
          }
      }
  },
  methods: {
      handleScroll() {
          // 防止某些手机浏览器不兼容"document.documentElement.scrollTop"
          const top = document.documentElement.scrollTop || document.body.scrollTop ||  window.pageYOffset
          if (top > 60) {
              let opacity = top / 140
              opacity = opacity > 1 ? 1 :opacity
              this.opacityStyle = {
                  opacity
              }
              this.showAbs = false
          }else{
              this.showAbs = true
          }
      }
  },
  mounted () {
      window.addEventListener('scroll',this.handleScroll)
  },
  destroyed(){
      window.removeEventListener('scroll',this.handleScroll)
  }

  }
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl'
    .header-abs
        position absolute
        left .2rem
        top .2rem
        width .8rem
        height .8rem
        line-height .8rem
        border-radius .4rem
        text-align center
        background rgba(0,0,0, .8)
        .header-abs-back
            color #fff
            font-size .4rem
    .header-fixed
        z-index 2
        position fixed
        top 0
        left 0
        right 0
        height $headerHeight 
        line-height $headerHeight 
        text-align center
        color #fff
        background $bgColor
        font-size .32rem
        .header-fixed-back
            position absolute
            top 0
            left 0
            width .64rem
            text-align center
            font-size .4rem
            color #fff 
</style>
